[ANN] Clojure 1.7.0-RC1 now available

[Alex Miller]

Clojure 1.7.0-RC1 is now available.

Try it via

- Download: https://repo1.maven.org/maven2/org/clojure/clojure/1.7.0-RC1/

- Leiningen: [org.clojure/clojure "1.7.0-RC1"]

The only change since 1.7.0-beta3 is CLJ-1706, which makes reader conditional splicing an error at the top level (previously it would silently drop all but the first spliced element).

For a full list of changes since 1.6.0, see:

https://github.com/clojure/clojure/blob/master/changes.md

Please give it a try and let us know if things are working (or not). The more and quicker feedback we get, the sooner we can release 1.7.0 final!

- Alex

[Sergey Didenko]

As I mentioned in another thread, how would you type hint an empty vector?

(set! *warn-on-reflection* true)
(java.util.ArrayList.  [])        ;Reflection warning
(java.util.ArrayList. ^java.util.Collection [])       ;Reflection warning

At the same time:

(java.util.ArrayList.  ["a"])          ;OK

P.S. May be it's offtopic, because I see the same behavior in Clojure 1.5.1

[Andy Fingerhut]

I believe this issue has been reported in this ticket: http://dev.clojure.org/jira/browse/CLJ-1093

Currently it is not planned to be fixed in Clojure 1.7.0.  Maybe a later release will fix it.

Andy 

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[Andy Fingerhut]

That may not be the right ticket.  Nicola Mometto may have the number memorized, if there is one :-)

Here is a workaround that avoids the reflection warning:

(let [^java.util.Collection x []]

  (java.util.ArrayList. x))

Andy

[Andy Fingerhut]

Alex, doing a quick sweep of new public Vars in 1.7.0-RC1 that were not in Clojure 1.6.0 (complete list of all 21 below), I noticed that the following two do not have any doc strings.  Intentional, or oversight?

*suppress-read*

Throwable->map

Andy

*suppress-read*

->Eduction

Throwable->map

cat

completing

dedupe

eduction

ensure-reduced

random-sample

reader-conditional

reader-conditional?

run!

tagged-literal

tagged-literal?

transduce

unreduced

update

volatile!

volatile?

vreset!

vswap!

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[Alex Miller]

Thanks Andy. Throwable->map should have a docstring.

[Jason Wolfe]

We haven't shipped it to production yet, but I just verified that our full test suite at Prismatic passes on RC1 after fixing a few tests that were erroneously depending on hash ordering.   Thanks everyone for all the hard work on this release!  

[Jason Wolfe]

Just deployed to our staging environment and ran into an unexpected stack overflow error.  Here's a reduced test case:

 

user> (->> (range 10000) (mapcat (fn [_] (java.util.ArrayList. (range 10)))) (reduce (constantly nil)))

java.lang.StackOverflowError: 

           RT.java:509 clojure.lang.RT.seq

          core.clj:135 clojure.core/seq

          core.clj:698 clojure.core/concat[fn]

       LazySeq.java:40 clojure.lang.LazySeq.sval

       LazySeq.java:49 clojure.lang.LazySeq.seq

   ChunkedCons.java:59 clojure.lang.ChunkedCons.chunkedNext

          core.clj:671 clojure.core/chunk-next

     protocols.clj:119 clojure.core.protocols/fn

      protocols.clj:19 clojure.core.protocols/fn[fn]

      protocols.clj:31 clojure.core.protocols/seq-reduce

      protocols.clj:75 clojure.core.protocols/fn

      protocols.clj:13 clojure.core.protocols/fn[fn]

     protocols.clj:152 clojure.core.protocols/fn

      protocols.clj:19 clojure.core.protocols/fn[fn]

      protocols.clj:31 clojure.core.protocols/seq-reduce

      protocols.clj:75 clojure.core.protocols/fn

      protocols.clj:13 clojure.core.protocols/fn[fn]

     protocols.clj:122 clojure.core.protocols/fn

      protocols.clj:19 clojure.core.protocols/fn[fn]

      protocols.clj:31 clojure.core.protocols/seq-reduce

      protocols.clj:75 clojure.core.protocols/fn

      protocols.clj:13 clojure.core.protocols/fn[fn]

     protocols.clj:152 clojure.core.protocols/fn

      protocols.clj:19 clojure.core.protocols/fn[fn]

      protocols.clj:31 clojure.core.protocols/seq-reduce

      protocols.clj:75 clojure.core.protocols/fn

      protocols.clj:13 clojure.core.protocols/fn[fn]

     protocols.clj:122 clojure.core.protocols/fn

      protocols.clj:19 clojure.core.protocols/fn[fn]

      protocols.clj:31 clojure.core.protocols/seq-reduce

      protocols.clj:75 clojure.core.protocols/fn

      protocols.clj:13 clojure.core.protocols/fn[fn]

     protocols.clj:152 clojure.core.protocols/fn

      protocols.clj:19 clojure.core.protocols/fn[fn]

      protocols.clj:31 clojure.core.protocols/seq-reduce

      protocols.clj:75 clojure.core.protocols/fn

      protocols.clj:13 clojure.core.protocols/fn[fn]

     protocols.clj:122 clojure.core.protocols/fn

      protocols.clj:19 clojure.core.protocols/fn[fn]

      protocols.clj:31 clojure.core.protocols/seq-reduce

      protocols.clj:75 clojure.core.protocols/fn

      protocols.clj:13 clojure.core.protocols/fn[fn]

     protocols.clj:152 clojure.core.protocols/fn

      protocols.clj:19 clojure.core.protocols/fn[fn]

      protocols.clj:31 clojure.core.protocols/seq-reduce

      protocols.clj:75 clojure.core.protocols/fn

      protocols.clj:13 clojure.core.protocols/fn[fn]

     protocols.clj:122 clojure.core.protocols/fn

      protocols.clj:19 clojure.core.protocols/fn[fn]

....

On Thursday, May 21, 2015 at 9:31:08 AM UTC-7, Alex Miller wrote:

[Daniel Compton]

One of the most significant features of 1.7 are Reader Conditionals. I'm pretty confident after all the discussion that has gone on that we have a good design. However I haven't seen many or any libraries which have gone through the porting process to use Reader Conditionals.

I've worked on porting a few libraries and everything has gone mostly smoothly. However I'd feel more confident that we've got the right design if we had more people trying to port their libraries/projects to cljc and reporting their experiences.

Is this a reasonable concern, or am I missing something and this isn't necessary?

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[Alex Miller]

That is interesting Jason - please file a ticket.

[Alex Miller]

Daniel, I have seen a number of reports from people successfully porting to use reader conditionals. A few issues have been reported and fixed. This rc period is when people should try it and report what they see.

[Ghadi Shayban]

This commit [1] for CLJ-1589 changed dispatch for InternalReduce, causing a bug similar to CLJ-1237 [2].

[1] https://github.com/clojure/clojure/commit/1242c4878f3d4ef30535a22f6c74144637504fbe
[2] http://dev.clojure.org/jira/browse/CLJ-1237

[Jason Wolfe]

Thanks for the context.  

It looks like this is actually the same as CLJ-1237, the scope of the issue is just broader now with that commit.  I left a comment there rather than creating a new ticket.  

[Mike Rodriguez]

This isn't necessarily a problem, but I figured I'd put it up in case anyone encounters similar or so that people can be aware of it coming.

We had some tests fail when I switched to the recent 1.7 versions of Clojure (beta3 was last I checked, but it shouldn't have changed here).

The Clojure compiler now seems to wrap many (most/all?) exceptions thrown with a Compiler$CompilerException.

We had some tests around macros that checked for certain exceptions being thrown - like ExceptionInfo or IllegalStateException etc. these were exceptions we explicitly through in macro error handling for compile-time error feedback with context.
We used the typically clojure.test is-thrown? Style which makes an instanceof assertion.

Arguably our tests were wrong to expect our macroexpansion exception types to be propagated all the way up to the caller without being wrapped first. However this was slightly surprising.

To be better prepared for future changes like this, it looks like we should assert no more specific than a RuntimeException (or possibly Exception, but I doubt Clojure would switch to checked exceptions).

[Alex Miller]

I'm not aware of any wholesale changes with respect to compiler exceptions. Can you give an example?

[Alan Moore]

I've started porting a library to use Reader Conditionals - I haven't seen any issues with it yet but my troubles are more related to the library and re-organizing the code than to RC specifically. I'll report back when I'm done...

Alan

[Mark Engelberg]

I noticed the other day, using beta 3, working at the REPL.  Some fairly mundane errors (I no longer remember what they were) were showing up in the stacktrace as Compiler Exceptions which completely threw off my intuition about where to look in my code for those errors.  So you're not alone, something definitely changed.

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[Marshall Bockrath-Vandegrift]

Some of my code is broken by commit c47e1bbcfa227723df28d1c9e0a6df2bcb0fecc1, which landed in 1.7.0-alpha6 (I lasted tested with -alpha5 and have been unfortunately busy since).  The culprit is the switch to producing seqs over iterators as chunked iterators.  This would appear to break seq-based traversal of any iterator implementing the not-uncommon Java pattern of mutating and re-yielding the same object on each `next()` invocation.

I'm unable to find an existing ticket for this apparent-regression.  Should I create one, or did I miss the existing ticket, or is there some mitigating issue which makes this a non-problem?

Thanks.

-Marshall

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[Alex Miller]

In what way is it broken? Both before and after wrapped a mutable iterator into a caching seq. The new one is different in that it chunks so reads 32 at a time instead of 1. However combining either with other chunking sequence operations would have the same effect which is to say that using that mutable iterator with anything else, or having expectations about its rate of consumption was as dubious before as it is now.

Unless of course I misunderstand your intent, which possible because I am on a phone without easy access to look further at the commit and am going by memory.

[Marshall Bockrath-Vandegrift]

The difference is that the original behavior allowed room to transform the mutated object into an object which *could* be safely cached in a "downstream" seq, while the new behavior pumps the iterator through 32 mutations before user-level code has a chance to see it.  Contrived example using the Java standard libary:

Clojure 1.6.0:

(->> (map vector (java.util.EnumSet/allOf java.util.concurrent.TimeUnit) (range)) (into {}) (java.util.EnumMap.) (.entrySet) (map str) (into []))

#=> ["NANOSECONDS=0" "MICROSECONDS=1" "MILLISECONDS=2" "SECONDS=3" "MINUTES=4" "HOURS=5" "DAYS=6"]

Clojure 1.7.0-RC1:

(->> (map vector (java.util.EnumSet/allOf java.util.concurrent.TimeUnit) (range)) (into {}) (java.util.EnumMap.) (.entrySet) (map str) (into []))

#=> ["DAYS=6" "DAYS=6" "DAYS=6" "DAYS=6" "DAYS=6" "DAYS=6" "DAYS=6"]

IMHO the latter behavior demonstrates a mismatch where chunked seqs and iterators are simple incompatible.

[Daniel]

Marshall, I'm unable to test at the moment, but if you replace

(java.util.EnumSet/allOf java.util.concurrent.TimeUnit)

with

(iterator-seq (.iterator (java.util.EnumSet/allOf java.util.concurrent.TimeUnit)))

will it work then?

[Daniel]

Got where I could try it and instantly became very confused.

Just...take a look.  http://imgur.com/4LgBdCY

On Tuesday, May 26, 2015 at 6:25:04 PM UTC-5, Marshall Bockrath-Vandegrift wrote:

[Leif]

Problem only arises with Clojure 1.7 + Java 1.6.

/usr/lib/jvm/java-8-oracle/jre/bin/java -jar ~/.m2/repository/org/clojure/clojure/1.7.0-beta3/clojure-1.7.0-beta3.jar
Clojure 1.7.0-beta3
user=> (->> (map vector (java.util.EnumSet/allOf java.util.concurrent.TimeUnit) (range)) (into {}) (java.util.EnumMap.) (.entrySet) (map str) (into []))

["NANOSECONDS=0" "MICROSECONDS=1" "MILLISECONDS=2" "SECONDS=3" "MINUTES=4" "HOURS=5" "DAYS=6"]

/usr/lib/jvm/java-7-oracle/jre/bin/java -jar ~/.m2/repository/org/clojure/clojure/1.7.0-beta3/clojure-1.7.0-beta3.jar
Clojure 1.7.0-beta3
user=> (->> (map vector (java.util.EnumSet/allOf java.util.concurrent.TimeUnit) (range)) (into {}) (java.util.EnumMap.) (.entrySet) (map str) (into []))

["NANOSECONDS=0" "MICROSECONDS=1" "MILLISECONDS=2" "SECONDS=3" "MINUTES=4" "HOURS=5" "DAYS=6"]

/usr/lib/jvm/java-6-oracle/bin/java -jar ~/.m2/repository/org/clojure/clojure/1.7.0-beta3/clojure-1.7.0-beta3.jar
Clojure 1.7.0-beta3
user=> (->> (map vector (java.util.EnumSet/allOf java.util.concurrent.TimeUnit) (range)) (into {}) (java.util.EnumMap.) (.entrySet) (map str) (into []))

["DAYS=6" "DAYS=6" "DAYS=6" "DAYS=6" "DAYS=6" "DAYS=6" "DAYS=6"]

--Leif

[Alex Miller]

That's not what I see with 1.7.0-RC1 (or any of the betas). I tried with both Java 1.7.0_25 and 1.8.0-b132.

user=> *clojure-version*

{:major 1, :minor 7, :incremental 0, :qualifier "RC1"}

user=> (->> (map vector (java.util.EnumSet/allOf java.util.concurrent.TimeUnit) (range)) (into {}) (java.util.EnumMap.) (.entrySet) (map str) (into []))

["NANOSECONDS=0" "MICROSECONDS=1" "MILLISECONDS=2" "SECONDS=3" "MINUTES=4" "HOURS=5" "DAYS=6"]

Re "implementing the not-uncommon Java pattern of mutating and re-yielding the same object on each `next()` invocation". I'm assuming that you're somehow expecting to traverse one seq node, then having an opportunity to mutate something (the source, the iterator, the return object) in between each new advancement of the seq node? That seems a) not common at all, b) a bad idea even in Java and c) dangerous even before this change. In either case you end up with a seq that points to a succession of the same repeated (mutable and mutating) object - this violates most expectations we as Clojure users have of sequences. Any sort of chunking (map, filter, etc) over the top of that seq would force realization up to 32 elements beyond the head causing the same issue. 

The original one-at-a-time IteratorSeq is still there (for now) and you can still make one if you want via (clojure.lang.IteratorSeq/create iter) but I would consider it deprecated. I think a custom lazy-seq or a loop-recur would be a better way to handle this case, which in my opinion is highly unusual. That said, my ears are open if this is an issue for a large number of people.

-Marshall

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[Julien]

I just ported an app with significant CLJX usage (55 files) to reader conditionals and it works perfectly!

It looks like there is a small issue related to map literal containing comments but I am not sure if it has been reported yet.

Julien

[Marshall Bockrath-Vandegrift]

Ugh -- looks like the iterator value re-use behavior for EnumMap entrySet was "fixed" post Java 1.6 (my example was under Java 1.6, which I believe is still a Clojure-supported version of Java?).  I can throw together a synthetic example, but I think the people following this thread get what's happening.  The point isn't whether this pattern is a "good idea" or not (it certainly isn't) but whether existing Java APIs people want to interop with use it (they certainly do).

I presently depend on no less than 3 separate Java library APIs I currently know for a fact depend on this behavior:

- Hadoop ReduceContextImpl$ValueIterator

- Mahout DenseVector$AllIterator/NonDefaultIterator

- LensKit FastIterators

It is an option to explicitly construct `IteratorSeq` instances (I actually had verified that approach this afternoon for the Hadoop API in Parkour), but I'm not happy about it. That approach places a definite burden on integration library maintainers to implement the change, and on end-users to realize they need to upgrade for Clojure 1.7 compatibility. The `Iterator` interface just fundamentally in no way guarantees that the `next()` yielded values are functional-safe in the sense necessary to support chunking. I understand the desire to increase performance, but I don't think it's worth the potential silent and bewildering breakage in interop.

-Marshall

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[Leif]

Object Pooling Considered Harmful?

I'd be willing to bet more libraries than just Hadoop are using object pooling like this, especially older libraries written before object instantiation was as fast as it is now.

So, if you are doing a lot of Java interop with libraries using object pooling, it's probably advisable to test against 1.7-RC.

--Leif

-Marshall

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[Marshall Bockrath-Vandegrift]

And to further explicate "bewildering" -- I mean that I only figured out what was happening because I was explicitly testing a library against 1.7.0-RC1 and even then had to `git bisect` *Clojure* to find the offending commit.  Otherwise the resulting behavior is just that values generated via the deep guts of a complex Java API suddenly became nonsensical.

[Mike Rodriguez]

I can see in Git several areas where the compiler now catches exceptions thrown and re throws them wrapped in this exception type. I've been out of town and unable to make a small example yet. I will soon.

[Mike Rodriguez]

Seems like this could certainly be an issue with any interaction with Hadoop's infamous reduce-side iterable object reuse. I will have to test further where I may be affected similarly.

[Alex Miller]

No, please report if so.

[Alex Miller]

On Tuesday, May 26, 2015 at 8:45:25 PM UTC-5, Marshall Bockrath-Vandegrift wrote:

Ugh -- looks like the iterator value re-use behavior for EnumMap entrySet was "fixed" post Java 1.6 (my example was under Java 1.6, which I believe is still a Clojure-supported version of Java?). 

Java 1.6 is still supported in Clojure 1.7 (but will likely be removed in the next release or two).

 

I can throw together a synthetic example, but I think the people following this thread get what's happening.  The point isn't whether this pattern is a "good idea" or not (it certainly isn't) but whether existing Java APIs people want to interop with use it (they certainly do).

The point I was getting at is really whether you should consider this to be broken with the old behavior too. 

 

I presently depend on no less than 3 separate Java library APIs I currently know for a fact depend on this behavior:

- Hadoop ReduceContextImpl$ValueIterator

- Mahout DenseVector$AllIterator/NonDefaultIterator

- LensKit FastIterators

Can you point to code for "the original behavior allowed room to transform the mutated object into an object which *could* be safely cached in a 'downstream' seq"? By what means does this transformation occur? It sounds to me like you are starting with an Iterator, creating a seq, then walking the seq exactly once, one element at a time, and producing a new transformed seq or other output. 

If you did reuse that IteratorSeq, all of the elements of the sequence would point to the same object which would be in the "last" state like the java 1.6 example you gave. Thus, the "caching" capability of the seq can't possibly be something you're using. And if that's true, then why are you paying the allocation and synchronization costs of making the seq at all? Why not just use the iterator directly, thus skipping all the extra allocation that these object-reusing high-performance iterators are working so hard to avoid in the first place? In 1.7, transducers would give you exactly the capability to walk the source iterator, apply a transducer version of your transformation, and output to a collection (via into), a value (via transduce), or a lazy sequence (via sequence). I think you would find this faster as well due to reduced allocation (possibly greatly reduced depending on the transformation).

 

It is an option to explicitly construct `IteratorSeq` instances (I actually had verified that approach this afternoon for the Hadoop API in Parkour), but I'm not happy about it. That approach places a definite burden on integration library maintainers to implement the change, and on end-users to realize they need to upgrade for Clojure 1.7 compatibility. The `Iterator` interface just fundamentally in no way guarantees that the `next()` yielded values are functional-safe in the sense necessary to support chunking. I understand the desire to increase performance, but I don't think it's worth the potential silent and bewildering breakage in interop.

It would be possible to restore the non-chunking IteratorSeq behavior but retain it for eduction and the other places where we first made the swap. I'm not quite ready yet to concede that that's necessary. It seems like the only constraints under which this usage makes sense is exactly the case where it's unnecessary and even harmful.

[Julien]

My bad I was using an older beta. With latest RC1 the issue goes away.

Julien

[Marshall Bockrath-Vandegrift]

On Tue, May 26, 2015 at 11:29 PM Alex Miller <al...@puredanger.com> wrote:

 

The point I was getting at is really whether you should consider this to be broken with the old behavior too.  

Such APIs are tricky to use correctly from Clojure via seqs, but it is possible to do so with the "normal" automatic clojure.lang.RT seq adapters in Clojure <=1.6. My point is that existing Clojure code can and does depend on non-chunked realization of iterator seqs, and that for such code this is a breaking change.

 

Can you point to code for "the original behavior allowed room to transform the mutated object into an object which *could* be safely cached in a 'downstream' seq"? By what means does this transformation occur? It sounds to me like you are starting with an Iterator, creating a seq, then walking the seq exactly once, one element at a time, and producing a new transformed seq or other output. 

Exactly -- the unfortunately Java <=1.6-only snippet I posted earlier is just such an example of this.

 

If you did reuse that IteratorSeq, all of the elements of the sequence would point to the same object which would be in the "last" state like the java 1.6 example you gave. Thus, the "caching" capability of the seq can't possibly be something you're using. And if that's true, then why are you paying the allocation and synchronization costs of making the seq at all? Why not just use the iterator directly, thus skipping all the extra allocation that these object-reusing high-performance iterators are working so hard to avoid in the first place? In 1.7, transducers would give you exactly the capability to walk the source iterator, apply a transducer version of your transformation, and output to a collection (via into), a value (via transduce), or a lazy sequence (via sequence). I think you would find this faster as well due to reduced allocation (possibly greatly reduced depending on the transformation).

I've personally used reducers wherever possible since they were introduced, and for the Hadoop case Parkour's primary recommended API is in terms of reducers [1]. For new code, the transducer-based facilities in Clojure 1.7 will certainly provide more options for functional-safe handling of the iterators at question.  But to repeat my main point, those don't help with existing code which depends on the one-at-a-time realization semantics of Iterators being reflected in one-at-a-time realization in iterator-backed seqs.

[1] https://github.com/damballa/parkour/blob/master/doc/reducers-vs-seqs.md

Thanks,

-Marshall

[Alex Miller]

I've logged http://dev.clojure.org/jira/browse/CLJ-1738 for this and I'll discuss with Rich.

[Tassilo Horn]

Hi Alex,

I've spotted another bug which I've already reported
http://dev.clojure.org/jira/browse/CLJ-1739. The problem is that sets
of different kinds are equal which is of course expected, e.g.,

(= #{1 2 3} (flatland.ordered.set/ordered-set 1 2 3)) ;=> true
(= #{1 2 3} (java.util.HashSet. [1 2 3])) ;=> true

but sets of equal sets aren't equal anymore, e.g.,

(= #{#{1 2 3}} #{(flatland.ordered.set/ordered-set 1 2 3)}) ;=> false
(= #{#{1 2 3}} #{(java.util.HashSet. [1 2 3])}) ;=> false

That's no recent regression in 1.7.0-RC1, though. I can reproduce the
bug also with 1.6.0.

Bye,
Tassilo

[Alex Miller]

This a dupe of CLJ-1372.

[Tassilo Horn]

Alex Miller <al...@puredanger.com> writes:

> This a dupe of CLJ-1372.

Yes, I guessed so and therefore mentioned CLJ-1372 in the description.

What about the other related issue I mentioned (CLJ-1649). Also a dupe
of CLJ-1372?

Bye,
Tassilo

[Alex Miller]

CLJ-1649 is separate and unrelated to what you logged.

[Andy Fingerhut]

Tassilo, the issue with flatland.ordered.set/ordered-set was that library had never been updated to match the change in hash function that occurred when Clojure 1.6.0 was released.

Alan Malloy released a new version of the ordered library today that fixes that.

That has no effect on the other CLJ tickets.  It is only a fix for the ordered library.

Andy

[Tassilo Horn]

Andy Fingerhut <andy.fi...@gmail.com> writes:

Hi Andy,

> Tassilo, the issue with flatland.ordered.set/ordered-set was that
> library had never been updated to match the change in hash function
> that occurred when Clojure 1.6.0 was released.
>
> Alan Malloy released a new version of the ordered library today that
> fixes that.

Indeed, I can confirm that it works as expected with version 1.5.3.

> That has no effect on the other CLJ tickets. It is only a fix for the
> ordered library.

Yes, of course.

Bye,
Tassilo

[Stephen Nelson]

I think I might have found a bug that affects multimethod dispatch
when using AOT. I've created an example repository:
https://github.com/sfnelson/clj-mm-dispatch

To me it seems similar to CLJ-979, my hypothesis is that defmethods
are using the wrong classloader to get class references. Is anyone
aware of existing open bugs along these lines?

On Fri, May 22, 2015 at 4:30 AM, Alex Miller <al...@puredanger.com> wrote:
> Clojure 1.7.0-RC1 is now available.
>

> Try it via
> - Download: https://repo1.maven.org/maven2/org/clojure/clojure/1.7.0-RC1/
> - Leiningen: [org.clojure/clojure "1.7.0-RC1"]
>
> The only change since 1.7.0-beta3 is CLJ-1706, which makes reader
> conditional splicing an error at the top level (previously it would silently
> drop all but the first spliced element).
>
> For a full list of changes since 1.6.0, see:
> https://github.com/clojure/clojure/blob/master/changes.md
>
> Please give it a try and let us know if things are working (or not). The
> more and quicker feedback we get, the sooner we can release 1.7.0 final!
>
> - Alex
>
> --

> Note that posts from new members are moderated - please be patient with your
> first post.

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[Geoff Shannon]

I just tried to upgrade a clj/cljs webapp I wrote. I got an error but it was just a transitive dependency issue with instaparse https://github.com/Engelberg/instaparse/issues/90.

Everything works great now that I'm using up-to-date dependencies!

[Mike Rodriguez]

Sorry for the delay in getting back with a response to this.  I think it is fairly clear in the Clojure Compiler that there is an exception that will wrap errors that occur during macroexpansion now.

Around here https://github.com/clojure/clojure/blob/master/src/jvm/clojure/lang/Compiler.java#L6627-L6649, the Compiler.macroexpand1() now has a try-catch for Throwable around the evaluation of the macro invocation.

This was not the case in Clojure version 1.6.  See around https://github.com/clojure/clojure/blob/clojure-1.6.0/src/jvm/clojure/lang/Compiler.java#L6548-L6560 for a reference point.

I'm fairly sure that is what has caused this change in behavior that broke our expectations that the exception types our code through during macroexpansion would propagate all the way back to the caller.  Again, I think this was a bad expectation to have, but it is a little tricky.

It is a little trickier for us to have any strong assertions on the type of exception that may come from a macro now.  Compiler$CompilerException seems too dependent on the implementation.  So we've opted to just assert there would be a is-thrown? RuntimeException in these sorts of tests.  If we want to test something like an ExceptionInfo's data map, we now just have to write a helper to walk the stack trace until we find it - which would likely be a single "step" up the trace.

A simple reproducing case:

*clojure-version* ;= {:major 1, :minor 7, :incremental 0, :qualifier "RC1"}

(defmacro demo [] (throw (ex-info "fail" {})))

(demo) ;= CompilerException clojure.lang.ExceptionInfo: fail {}, compiling:(form-init4053282905768384039.clj:1:1) 

vs.

*clojure-version* ;= {:major 1, :minor 6, :incremental 0, :qualifier nil}

(demo) ;= ExceptionInfo fail  clojure.core/ex-info (core.clj:4403)

On Saturday, May 23, 2015 at 8:52:47 AM UTC-5, Alex Miller wrote:

I'm not aware of any wholesale changes with respect to compiler exceptions. Can you give an example?

[Ivan L]

Removing Java 6 would affect clojure for android projects wouldn't it?

[Andy Fingerhut]

Just to provide slightly more info, that change was made because of this ticket: http://dev.clojure.org/jira/browse/CLJ-1169

Andy

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[Alex Miller]

Thanks Ivan and Andy, I'd appreciate a ticket in jira if only to consider this again before release.

Thank goodness Stu H screened that one so I can blame him. ;) 

[Alex Miller]

s/Ivan/Mike Rodriguez/ sorry :)

[Alex Miller]

This is the kind of thing that would be considered before making the decision. But it's coming eventually.

[Andy Fingerhut]

I've filed http://dev.clojure.org/jira/browse/CLJ-1745

In checking Mike Rodriguez's test case for reproducing the issue, I could reproduce the behavior change in a lein repl, but the behavior appears to be the same with a plain Clojure REPL.  See the ticket for what I found, and feel free to edit in case anyone else gets additional results that differ from those.

Andy

[Sean Corfield]

We took RC1 to production yesterday afternoon (after being on beta1 since mid-April). So far so good.

I think the only 1.7 new feature we’re using so far is transducers (we wrote a transducer that takes a result set of user-to-user messages and returns a paginated, nested result set organized by conversion thread — a big simplification over how we’d done it before).

Sean

[Luc Prefontaine]

Hi,

Have been using 1.7 since beta1 in dev and test in a new dev.
Still 3 months away from production beta.

So far no issues. Zero, nada, nil, ...

Reader conditionals are quite amazing, we started unifying backend and front end code.
Wow... No more split brain syndrome and a huge simplification of front end/back end code.
That's a huge relief on my nervous system :)

For the first time in many years I enjoy working on a web front end... finally.

Thank you all,

Luc P.

On Thu, 21 May 2015 11:30:47 -0500

Alex Miller <al...@puredanger.com> wrote:

> Clojure 1.7.0-RC1 is now available.
>
> Try it via
> - Download:
> https://repo1.maven.org/maven2/org/clojure/clojure/1.7.0-RC1/
> - Leiningen: [org.clojure/clojure "1.7.0-RC1"]
>
> The only change since 1.7.0-beta3 is CLJ-1706, which makes reader
> conditional splicing an error at the top level (previously it would
> silently drop all but the first spliced element).
>
> For a full list of changes since 1.6.0, see:
> https://github.com/clojure/clojure/blob/master/changes.md
>
> Please give it a try and let us know if things are working (or not).
> The more and quicker feedback we get, the sooner we can release 1.7.0
> final!
>

> - Alex
>



--
Luc Préfontaine

SoftAddicts inc.
Québec, Canada
Mobil: +1 (514) 993-0320
Fax: +1 (514) 800-2017

Rabat, Maroc
Mobil: +1 212 6 98 00 64 47

[Sean Corfield]

On Jun 4, 2015, at 2:51 PM, Luc Prefontaine <lprefo...@softaddicts.ca> wrote:
> Still 3 months away from production beta.

I get twitchy if we go more than two weeks between production builds — but then it’s the web :)

Sean Corfield -- (904) 302-SEAN
An Architect's View -- http://corfield.org/

"Perfection is the enemy of the good."
-- Gustave Flaubert, French realist novelist (1821-1880)

[Mike Rodriguez]

Thanks Andy for the extra info and for logging the follow-up Jira!
It looks like the exception changes are expected and are a potential improvement with line numbers etc.
My the main goal was just to provide constructive feedback on here of the issues I faced investigating the upgrade of a fairly large code base from Clojure 1.6 to 1.7.

I appreciate all the feedback from everyone.

[Luc Prefontaine]

We have a planned upgrade at a customer site before xmas of our oldest product. Internal work on upgrading it to 1.7 starts in august.

If I look at the Clojure upgrade track since 2009, I can't say that I am nervous about this.

Not at all :)

We are presently building a new product and integrating 1.7 made sense. We already reused some common internal components w/o any glitches.

25 years ago I was used to smooth upgrades working on VMS.

I did not see that happening many times since then.

And we run critical services 24/7 on premises, not in a fully controlled off-site environment. Our up times are insane.

Yahoo !
Luc

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